Shock absorber



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H. B. SHAEFFER SHOCK ABSORBER Filed Aug. 9 1.922

4 Sheets-Sheet -3 H. B. SHAEFFER SHOCK ABSORBER Filed Aug. 9

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Application filed August 9, 1922. Serial No. 580,682.

To all whom it may concern:

Be it known that I, HARRY B. SEAEFFER, a citizen of the United States, residing at the city of Altoona, county of Blair, State a of Pennsylvania, have invented certain new and useful Improvements in Shock Absorbers; and I do hereby declare, the fol I lowing to be a full, clear, and exact de scrlption of the'inv'ention, such as will enlo able others skilled in the art to which it appertains to make and use the same.

The invention relates to shock absorbing devices or snubbers for automobiles and the like, and has for its object to provide a is simple and eficient device of this character having a wide range of action, and a high degree of flexibility, that is compact in structure, easy of application, and practically immune from derangement, as will be more 20 particularly pointed out in the specification, predicated on the accompanying drawings, in which,

Fig. 1 is a ront elevation of the preferred form of the invention;

Fig. 2 is a vertical section on line 22 of Fig. 1; v

Fig. 3 is a front elevation with the cover alate removed and portions of the interior mechanism in sactional elevation;

Fig. 4 is a front elevation of a modified form of the apparatus;

Fig. 5 is a section on line 5-5 of Fig. 1; Fig. 6 is a sectional front elevation; Fig. 7 is a plan view; 5 Fig. 8 is a rear elevation of the face plate and associated parts;

Fig. 9 is a plan view of the spring drum and frame associated therewith;

' Fig. 10 is a front elevation of the same Fig. 11 is a front sectional elevation of a modified form of the device;

Fig. 12 is a section on line 12-12 of Fig. 11;

Fig. 13 is a 45 special form of coking means.

Referrin to Figs. 1, 2and 3 of the drawings, 1 indicates-a supporting base or casin generally cylindrical in shape, having a hracket 2 associated with the back wall so and adapted to secure the casing to the chassis or body portion of the vehicle, as will be understood. The casin 1 may be formed either of cast or stampe metal and is provided with a suitable cover plate 3 es secured position by any appropriate artial elevation showing a.

means, such for example, as small bolts, as illustrated.

Mounted in aligning openings in the back of the casing 1 and the cover plate 3, is a shaft 4 upon which is loosely mounted a cylindrical drum 5, which is connected to t e shaft 4 by means of a spiral sprin 6. The tension of the 3 ring 6 may be regfiated by rotating the s haft a by means of the squared head 7 thereon, while the drum is held relatively stationary, and then looking the shaft by a set-screw 9 passing through a collar 8 fast to the shaft, said set-screw being adapted to engage any one of a circular series of bolt openings 10 in the cover plate 3.

Rotatably mounted on the shaft 4 and surrounding-the drum 5 is a frame, which is preferab y in the form of a hollow cylinder or drum 11 having a detachable cover plate 12, the side wall of the frame being interrupted to rovide an opening in which is mounted a s aft 14. upon which is journalled a (pulley 13. A friction band 15, the outer en of which is secured to the wall of the casing 1 passes around the pulley 13 and then in reverse direction around the surface of the drum 5, to which the other end of the said band is secured at 16.

Secured at 22 to the outer surface of the drum-like frame 11, is a strap 20," which passes around the peripheral surface of the frame and out through the opening in the casing 1, and has its lower end looped about the axle B or other suitable element of the running gear efthe vehicle, the loop being secured in position by a suitable clam 21.

The device is ap lied to an automo ile or other vehicle by c amping the casing 1 to the frame A of the chassis and securing the lower looped end of the strap 20 to the axle B, or, if desired, to the adjacent spring or other element of the running gear. Under normal conditions, the strap 20 will be stretched taut between its anarc chor points on the axle 1B and the surface of the frame 11, and similarly the friction band or stra 15 will be held taut between its points 0 connection on the stationary casing 1 and the surface of the spring we drum 5. When the machine encounters an obstruction to cause the supporting springs to yield and the body to be depressed the tension of the spiral spring on the drum 5 ill a s h l ter. to revolve and the ne fit) till

sudden rebound of the latter is clinched smoothly and gradually by the conjoint action of the spring drum, the frictional n,- sistance reduced between the belt 15 and the perip iera-l surface of the frame 11 and the normal insistence of the strap or band 15 to deformation, as said band is drawn around the pulley or roller 13. It will be noted that the edcct of the pulley 13 is to increase the ratio of travel of the belt or band 15 and the strap 20 to approximately 2 to 1. In other words, for every inch of travel of he strap 20, the belt or hand 15 will move two inches over the periphery of the spring drum, and produce a corre- -sponding deflection. of the spiral spring.

Assume, for example, that every inch of deflection of the spiral spring produced by corresponding travel of the band 15 results in a pulling force of ten. pounds, then for every inch of travel of the strap 20 the torn sion or reaction of the spring will be 1ncreased by twenty pounds While this factor, in itself, would tend to materially reduce the shocks and jars due to rebound of the vehicle body, this desirable result is materially enhanced by the relatively large element of frictional resistance produced by the peripheral surface of the frame 11 m0V ing over the belt or band 15, while the latter is stretched taut between. its point of anchorage on the casing and the pulley 13, as said frame 11 is rotated by the pull on the strap 20. It will be noted. that the strap or band 15 makes an abrupt turn about the pulley l3 and the normal resistance of said strap or band to any change in its direction of movement or deformation of its shape produces a further element of resistance to the rebound of the car body. It will be seen, therefore, that the device, in its normal snubbing operation produces three coordinated resistance factors which will revent any sudden rebound of the vehicle ody, but will cause the latter to resume its normal position gradually and smoothly and without appreciable shock or jar, said factors being the augmented tensionable resistance of the spring drum, the frictional resistance between the periphery of the frame 11 and the strap or band 15, which is proportional to the tension on said strap or band, and the resistance of the strap or band 15 to deformate and change the direction as it runs over the pulley 13., If desired this last mentioned resistance element may be materially increased by adding a second pulley mounted in the easing 11, adjacent the pulley 13, whereby the strap or band is forced to make a double bend over the two pulleys but, under ordinary circumstances the single pulley 13 will suffice. V i

From the foregoing description it be apparent that the device may be made relatively light and will occupy a very small amount of space, and can be readily applied to or I'QIHOVECl from its appointed position on the vehicle without mutilating any parts of the latter or providing specific securing devices in connection therewith. lit will also be ap arent that the apparatus is capable of a re atively wide range of adjustment'to accommodate conditions on cars of varying weights and sizes, by regulating the tension of the spring 6, which may be quickly effected by the simple means provided.

A somewhat different physical embodiment of the same general structure and operative principles of the invention is enemplified in Fig. 4 to 10 inclusive, which is particularly adapted to heavy cars and trucks, in which the rebound or force of the reaction between the body and the springs is much heavier than in the lighter cars. In this form of the apparatus, the casing 1 is substantially elliptical in shape, and provided on its rear face with a clamping bracket 2' similar to that illustrated in the first form. The lower wall of the casin is cut away for a considerable distance, as shown in Fig. 6 A suitable cover plate 3' is removably secured to the casing by means of ordinary machine screws. Journalled in suitable openings in the rear. wall and cover plate of the casing is a shaft 4' upon which is mounted a drum 5' within which is the spiral spring 6 having one end connected to the inner wall of the drum and the other to the shaft 4!. The outer end of'the shaft a is provided with a wrench head 7' by means of which the shaft is retated to apply the desired tension to the spiral. spring 6. In order to retain. the tension applied to the spring 6', the shaft l has fixed thereon a ratchet 8' located be tween the drum 5' and the cover plate 3' which ratchet is engaged by a spring-pressed pawl 9, as shown in Figs. 4 and 8. Secured to a stud 10" mounted on the cover late 3 ill lid

meters mounted in the back of the casing 1' and the cover plate 3', the latter ulley being mounted above and between t e drum 5' and the pulley 13', as illustrated in Fig. 6. A friction stra or band 15' is connected at one end to tie's'urface of the drum 5, and extends around the periphery of the drumfthence upward and over the pulley 16', downward and under the pulley 13 carried by the pivoted frame 11', and thence upward to its point of anchorage 18 on the inner wall of the casing 1'.

The outer end of'the pivoted frame 11' is connected by a strap or other suitable flexible link 20 with some element of the running gear of the machine, as for example, the axle B, in which latter case the lower end of the strap 20' is looped about the axle and secured to the body of the strap by a clamp 21'.

The operation of this form of the apparatus is similar to that first described. When the part A of the vehicle is depressed on the supporting springs, upon meeting an obstruction in the roadway, the slack in the strap 20 isimmediately taken up by the spiral spring 6', which rotates the drum 5 to wind the strap 15' thereon, and the parts assume the relation shown in Fig. 6. When the vehicle springs react and the body of the vehicle tends to move upward, the

otherwise rapid upward movement of the body, which would impose heavy strains on the machine and cause great inconvenience to the passengers, is checked or arrested by the resistance'of the spring 6 the frictional resistance between the stra or band 15' the pulleys 16' and 13, and the resistance produced by the change of form of the strap or band 15' as the latter passes over the pulleys 13' and 16.

The modification illustrated in Figs. 11,

12, and 13 difi'ers only in detail from that shown in Figs. 1 to 3 inclusive and the principle of operation of the two devices is identical. In lieu of the casing 1, as employed. in the first modification, there is provided a base or support 101 provided with shoulders 101', adapted to engage the flanges of the longitudinal member A of the chassis frame, as shown in Fig. 12, said base or support being secured to the member A by means'of a bolt 102 tapped into said base and passing through a hole in the member A and preferably locked in position by nuts 102-. The member 101 is provided with an integral shaft-like extension 104, which is preferably hollow and has mounted thereon a sleeve 104:.

A spring drum 105, mounted on the shaft 104 and sleeve 10 1 is provided with a spiral spring 106 having one end connected to the interior face of the drum and the other end to the sleeve 104:.

In order to regulate the tension of the spring 106 the outer end of the sleeve 104' is provided with a squared section 107 to receive a wrench by means of which the sleeve may be rotated, thereby either windin or unwinding the spring 106. In order to hold the tension of the spring 106, a special form of locking device is provided, comprising a cross-bar 108', engaged by a bolt 110 tapped into the end of the shaft 104, the ends of cross-bar 108 engaging slots 108 and 109 formed in theends of the shaft 104 and the sleeve 10; respectively. A. helical spring 110' surrounding the bolt 110 serves to disengage the crossbar from locking engagement from the slots aforesaid when the bolt 110 is backed out. Revolubly mounted on the shaft 104 and the sleeve 104' is a drum-like frame '111 hav ing an' opening in its peripheral surface adjacent which is mounted a pulley 113 on a shaft 114%. A friction strap or band 115 is secured at 116 to the surface of the drum 105 and passes over the pulley 113 and is anchored at its outer end to a suitable bracket 118* attached to the vehicle body, or to the base 101.

Secured at 122 to the periphery of the frame 111 is a strap 120 which passes around the peripheral surface of said frame and has its lower end looped about the axle B or other element of the running gear of the vehicle, the loop being secured to a suitable clamp 121.

As indicated, the operation of this form of device is identical with that shown in Figs.- 1 to 3 and is practically equivalent to that of the device shown in Figs. 4 to 10 inclusive. The normal relation of the various elements of the snubbing 'device, when the vehicle body is at its normal distance from the chassis, is that illustrated in Fig. 11. When the vehicle body is depressed and the tension on strap 120 is released the drum 105 will be. rotated in an anticlockwise direction by spring 106, which rotates the frame 111 by drawing the strap or band 115 around the periphery of said drum and over the pulley 113. The extent of movement of the drum 105 and frame 111 will be roportional to the downward movement 0? the vehicle body and, 'due to the tension of the spring 106, the rotation of both the body and drum will be practically instantaneous. When the vehicle body tends to rise or rebound, due to the action of the vehicle springs, the same checking or braking-forces will be called into operation. as in the operation of the device illustrated in Figs. 1 to 3, namely the resistance of the spiral spring 106, the friction between the peripheral surface of the frame 111 and strap 115, and the resistance of the strap 115 to constantly changing deformation, as it passes about the pulley 113. The extent of frictional engagement between the lltv ill)

surface of frame 111 and belt 115 will be indicated by comparing Figs. 3 to 11. In Fig. 3 the friction strap or band is entirely out of engagement; with the peripheral surface of the frame 11 and the parts are in relative position when the vehicle bod is in its lowermost position and the vehic e spring have been depressed to the maximum.

soon, however, as the vehicle body starts to rise the strap 115 begins to engage the peripheral surface of frame 111. and this sliding frictional engagement between the frame and belt is continued until the parts reach their relative positions shown in Fig.

11, when the vehicle frame has reached its normal position, with respect to the chassis. It will, therefore, be seen that the extent of engagement between the surface of the frame and the friction strap or band, in each of the modifications, is represented by the angle X in Fig. 11 and the amount of friction developed will be directly proportional to the pressure exerted by the strap or band, and this in turn will be determined by the pull exerted on the strap or band by the spring drum.

In the several modified forms of the invention the effect of the three forces or resistances tending to check the rebound of the springsand "the vehicle body is positively but gradually applied so that the device operates with exceptional smoothness and practically eliminates the objectionable sudden rebound of the vehicle body.

What I claim is:

1. A shock absorber comprising a spring drum adapted to be attached to one of two relatively movable parts, a frame pivoted coaxially with said drum, a pulley carried by said frame, a band engaging the surfaces of the drum and pulley secured at one end to the drum and at the other to a fixed anchorage, and means connecting the frame and the other of the said relatively movable parts.

2. A shock absorber comprising a 5 ring drum adapted to be attached to one 0 two relatively movable parts, a frame pivoted coaxially with said drum, a pulley carried by said frame, a band engaging the surfaces of the drum and pulley secured at one end to the drum and at the other to a fixed anchorage, and a flexible link connecting the frame and the other of the relatively movable parts.

3. A shock absorber comprising a support adapted to be attached to one of two relatively movable parts, a spring drum journalled thereon, a frame journalled coaxially the frame and the other i with said drum,

eant/a with said drum, a pulley carried by said frame, a band engaging the surfaces of said drum and pulley having its ends attached to said drum and support respectively, and a flexible link connecting the frame and the other of the said relatively movable parts.

4. A shock absorber comprising a support adapted to be attached to one of two relatively movable parts, a shaft thereon, a drum on said shaft, a springhaving its ends connected to the shaft and drum respectively, a frame journalled on said shaft, a pulley carried by said frame, a band engaging the surfaces of the drum and pulley and having its ends'oonnected to said drum and support respectively, and a flexible link connecting of said relatively movable parts.

5. A shock absorber comprising a support adapted to be attached to tively movable parts, a shaft mounted thereon, a drum on said shaft, a spring having its ends connected to the shaft and drum respectively, means for adjusting the tension of said spring, a frame journalled on said shaft, a pulley carried by said frame, a band engaging the surfaces of the drum and pulley and having its ends connected to said drum and support respectively, and a flexiblc link connecting the frame and the other of said relatively movable parts.

6. A shock absorber comprising a cylindrical casing adapted to be attached to one of two relatively movable members, a spring drum journalled in said casing, a substantially cylindrical frame journalled coaxially with said drum, a pulley carried by said frame, a band engaging the surfaces of said drum and pulley and having its ends secured to the drum .and frame, and a flexible link connecting the frame and the other of said relatively movable parts.

7 A shock absorber comprising a cylindrical casing adapted to be attached to one of two relatively movable members, a spring drum journalled in said casing, a substantially cylindrical frame journalled coaxially a pulley carried by said frame, a band engaging the surfaces of said drum and pulley and having its ends secured to the drum and frame, and a flexible link engaging the surface of said frame having one end attached to the frame and the other end to the other relatively movable parts. e

ture.

HARRY l3. SHAEFFER.

In testimony whereof I affix my signatill one of two rela- 

